EP0117297B1 - Feed device for straw-burning apparatus - Google Patents

Abstract

1. Feed device for straw-burning apparatus with a bale storage arrangement (1) and a bale loosening device (16), which passes the loosened straw through a charging opening (18) to a horizontal pressing channel (19) normal to its longitudinal direction, in which a piston (23) is movable back and forth, which compacts the lossened straw and conveys it to the combustion furnace, the movements of the bale loosening device (16) and the piston (23) being co-ordinated with each other in terms of time, characterized in that a vertical shaft (1) is arranged laterally adjacent to the pressing channel (19) to receive the straw bale and beneath the shaft (1) there is provided a scraping plate (16), which is rotatable back and forth about a vertical axis (11), with tearing teeth (58) which are effective only in one direction of rotation (63), for engagement on the straw bale (2) lying above, which plate on the return movement of the piston (23) from its forward position (28) into the rearward position (29) scratches off the straw from the underside of the bale and pushes it through the charging opening (18) into the pressing channel (19).

Description

The invention relates to a loading device for straw incineration plants with a bale storage device and a bale breaker, which feeds the dissolved straw through a filling opening to a horizontal press channel perpendicular to its longitudinal direction, in which a piston can be moved back and forth, which compresses the dissolved straw and to the incinerator promotes, the movements of the bale breaker and piston are coordinated in time.

Such a device can be found in DE-A 3005039. Here, a conveyor chain pushes the bales lying on it to a bale portioner that can be moved up and down perpendicularly to the direction of feed of the bales and that cuts off a straw layer from the front bale and presses it into the baling channel from above. The bale portioner closes the filling opening of the baling channel until the piston has pushed the pre-compacted straw out of the area of the inlet opening. With each piston return stroke, the conveyor chain is advanced by a constant amount.

It has been shown to be disadvantageous in such a device that, depending on the thickness of the cut-off layer, uneven ejection lengths of the press packs result. However, press pack lengths that are as uniform as possible are a prerequisite for uniform and complete straw burning. The disadvantage is not only due to the controlled assignment of the bale feed to the bale portioner, but also due to the principle of portioning a straw bale by parting off individual layers using a cutting edge and pressing the layers into the press channel. A straw bale formed in a conventional high-pressure piston press is composed of individual pressed stalks packs, which can already have different densities and thicknesses from one another, so that deviations would occur even when parting off between the packs, which is not practical with this device. When parting off in the pack, the interwoven crop structure counteracts the separation, so that the pack is not pre-compressed downwards into the press channel in the predetermined space, but breaks out laterally, which results in uneven filling of the press channel and different pack lengths.

Scraper plates for dissolving bales of straw are known per se. EP-A-56 425 shows and describes a bale breaker which is formed by a number of knife rollers which can be rotated about horizontal axes and are arranged side by side on the bottom of a vertical receiving container for large bales. Each knife roller has knives distributed over its circumference, which mill the bale. It is disadvantageous that the bale has no form-fitting guidance, so that the disintegration occurs irregularly and an additional metering roller between the milling roller and the press piston is required. The straw also wraps around the rollers and causes malfunctions.

A scraper plate with knives that constantly rotates about a horizontal axis of rotation is known from FR-A-2 420912. This interacts with fixed counter knives to chop the straw so that the straw can then be digested, for example with sodium hydroxide solution.

The invention is based on the object of designing a loading device of the type described at the outset in such a way that a trouble-free, uniform and energy-saving separation of the material from the bale and a good filling of the baling channel is ensured for every type and every condition of the material, regardless of the bale density, so that everyone Piston stroke an equal pack length is achieved.

This object is achieved according to the invention in that a vertical shaft for straw bale pick-up is arranged on the side next to the pressing channel and below the shaft there is a scraper plate that can be rotated back and forth about a vertical axis with fangs that are effective in only one direction of rotation for attacking the straw bale lying above it which, when the piston moves back from its front position to the rear position, scrapes the straw from the underside of the bale and pushes it through the filling opening into the baling channel. With such an arrangement, a straw bale that automatically moves upwards in the vertical shaft due to its own weight lies directly on the scraper plate, the fangs of which stick directly into the front of the bale from below and tear away a certain amount of straw, take it along and push it into the empty press channel without substantial compaction, which is a uniform one Filling of the press channel as a prerequisite for the same press pack length guaranteed with every piston stroke.

Favorable engagement conditions in the straw bale and a safe take-away of the torn straw amount result if the fangs of the scraper plate are designed as pointed tines which engage at an acute angle in the surface of the bale to be removed.

Since the scraper plate, like the piston, reciprocates, a simple, reliable and low-maintenance drive can be achieved in that the drive of the scraper plate is mechanically coupled to the piston drive in a preferred embodiment. For a good filling of the baling channel, it is expedient if the scraper plate assumes a position in the rear piston position in which a group of tines projects into the baling channel and the conveying direction of another group of tines extends approximately perpendicular to the longitudinal direction of the baling channel.

So that the straw cut off at the knife edge in the cylinder chamber is not too undesirable Leads to accumulations, which can be the cause of malfunctions, the invention proposes that the scraper plate assumes a position in the forward position during the movement of the piston, in which at least one prong attached laterally adjacent to one at the front end of the filler opening on the ceiling wall , with the piston cooperating knife, and that this tine tends to catch straw hanging on the knife during its return movement and feeds it again to the filling opening.

Another feature suggests that the cylinder space connects laterally to the press channel and opens into the filling opening of the press channel. This enables a compact, space-saving design.

Since the filling of a press channel depends not only on the feed and the size of the filler opening, but also on the press channel cross-section, the filling can be favorably influenced for a given feed pipe cross-section of the firing system by increasing the press channel cross-section in the area of the filler opening and following it Filling opening is reduced to a cross-section of the feed tube by means of a transition piece designed as a shear bar and interacting with the piston.

Further advantageous developments are set out in the subclaims.

• Fig. 1 eine Seitenansicht der erfindungsgemässen Vorrichtung bei hinterer Kolbenstellung mit einem senkrechten Querschnitt durch den Zylinderraum entlang der Schnittlinie C-D in Fig. 4.
• Fig. 2 einen senkrechten Querschnitt bei vorderer Kolbenstellung entlang der Schnittlinie A-B in Fig. 3.
• Fig. 3 eine Draufsicht auf die gesamte Vorrichtung bei vorderer Kolbenstellung.
• Fig.4 eine Draufsicht bei hinterer Kolbenstellung.

The invention is explained below with reference to an embodiment shown in the drawing. Show it:

• 1 shows a side view of the device according to the invention in the rear piston position with a vertical cross section through the cylinder space along the section line CD in FIG. 4.
• FIG. 2 shows a vertical cross section with the piston in the forward position along the section line AB in FIG. 3.
• Fig. 3 is a plan view of the entire device in the front piston position.
• 4 shows a plan view with the piston in the rear position.

The loading device consists of a vertical shaft 1 with a rectangular cross-section for receiving straw bales 2, in particular conventional, rectangular high-pressure pressed bales with a weight of the order of 30 kg and a transverse dimension of approximately 0.40 x 0.50 m. The shaft cross section is dimensioned somewhat larger, so that a straw bale 2 inserted in the longitudinal direction can slide downwards, but cannot be rotated in the shaft 1. A ramp, not shown, with a driven scraper floor for transporting the straw bales 2 into the shaft 1 leads to the upper shaft mouth.

On a shaft wall 3, a rod 4 is suspended in an oscillating manner about a horizontal bolt 5 situated at a high level. The lower, free rod end ends just above a lower shaft opening 6 and carries a knife blade 7 which projects into the shaft 1 through a wall slot 8 running along the pendulum path, so that a bale strapping 9 (FIG. 1) shown in dash-dotted lines passes through during the pendulum movement the knife blade 7 is cut. The rod 4 is driven in a manner to be described later.

The shaft 1 opens downwards into a cylinder chamber 10 with a vertical central axis 11, which is approximately coaxial to the longitudinal axis of the shaft and the cylinder jacket 12 of which extends over its entire circumference outside the rectangular shaft cross section. The upper end face 13 of the cylinder space 10 has a passage opening for the straw bale 2 corresponding to the shaft opening 6, while a scraper plate 16, which will be described in detail later, is arranged directly above the lower, closed end face 15.

A cylinder segment is cut away from the cylinder space 10 outside the shaft 1 in parallel and at a short distance from the shaft wall 3 (FIG. 3), so that a rectangular opening is created in the vertical plane, which has an equally large filler opening 18 which adjoins the cylinder space 10 laterally , horizontal press channel 19 coincides, the longitudinal direction of which runs parallel to the filling opening 18. A piston 23 with a round cross section is arranged in the press channel 19. The cylinder chamber 10 and the press channel 19 have vertical support feet 22. The press channel 19 has a rear and a front section. The rear section, which extends from an end face 26 to the end of the filling opening 18, has a cross section which is formed from a semi-cylindrical bottom wall 20 and a U-shaped top wall 17 bent downwards. The bottom wall lies close below the lower end face 15, while the top wall 17 lies above the upper end face 13. A side wall 21 opposite the fill opening 18 connects the bottom wall 20 to the top wall 17. On the fill opening side, the rear press channel section between the bottom wall 20 and top wall 17 has an open cross section, the height of which corresponds to the distance between the end faces 13, 15. In the area of the filling opening 18, the top wall 17 is connected to the upper end face 13 and the bottom wall 20 to the lower end face 15. The front section of the press channel 19, which begins at the end of the filling opening 18, is designed as a feed pipe 36, which has the same diameter as the bottom wall 20 and leads to an incinerator, not shown.

The step between the ceiling wall 17 and the feed pipe 36 is completed by an end plate 37. On its side facing the rear press channel section, the latter carries a transition piece 38 which is adapted to the rounding of the piston and which has the rectangular cross section of the ceiling wall 17 on the round coating reduced pipe cross-section. The transition piece 38 has on the lower edge a slope rising away from the feed pipe 36. On the one hand, it guides the piston 23 into the feed pipe 36 during the movement, on the other hand it forms a shear bar for separating material from the channel space above the piston 23.

The filling opening 18 is bounded at the front by a knife 32 running in a vertical plane, which is fastened to the ceiling wall 17 with screws 34 and the cutting edge 33 of which begins at the top edge of the piston and drops obliquely to the bottom edge of the piston. The underside of the knife passes through a slot in the lower end face 15.

The piston 23 consists of a hollow cylinder 25 and a piston end wall 30. Its length is greater than the length of the filling opening 18. It is slidably mounted on the bottom wall 20 and is guided from above by a guide piece 24 fastened to the ceiling wall 17, the guide surface of which Piston rounding is adjusted. Arranged in the hollow cylinder 25 between the piston 23 and the end face 26 of the press channel 26 is a pressure cylinder 27 which can be pressurized with pressurized oil and which moves the piston between a front position 28 (FIGS. 2, 3) and a rear position 29 (FIGS. 1, 4) - And moves here, the piston end wall 30 being in both positions 28, 29 outside the fill opening 18. The piston end wall 30 has a cutting edge 31 formed by wedge-shaped recesses along its circumference. During the piston movement from the rear 29 into the front position 28, this first interacts with the knife 32 and then with the transition piece 38.

The scraper plate 16 and its drive are described below. The scraper plate 16 has a triangular shape with a size that corresponds to approximately a quarter of the cylindrical end faces 13, 15 and is arranged directly above the lower end face 15. A pin 40 is fastened to the underside of the scraper plate about half the length of a curved triangular side 39 and passes through the end face 15 coaxially to the central axis 11 and is mounted in a hub 41 below the end face 15. A crank 42 is fastened to the pin end with a cross pin 43. The crank 42 is articulated via a coupling 44 to a rocker 45 which is rotatably supported on a pin 46 which is welded to the underside of the bottom wall 20. The four-link mechanism 42, 44, 45 thus formed is connected to the piston 23 via a rod 47 which engages on the one hand in the coupling joint 14 and on the other hand is articulated with a bolt 48 in two brackets 49 welded to the piston 23. The position of the pin 46 and the lengths of the crank 42, the coupling 44 and the rocker 45 are selected such that the scraper plate 16 assumes a position 50 (FIG. 3) in the front piston position 28, in which a straight triangular side 51 in the filler opening 18 lies, while the scraper plate 16 assumes a position 52 (FIG. 4) in the rear piston position 29, in which a scraper plate section 53 projects beyond the filling opening 18 into the press channel 19. The four-bar linkage 42, 44, 45 is also designed so that when the piston moves from its rear 29 to its front position 28, the scraper plate 16 initially moves quickly back out of the press channel 19, while the scraper plate 16 in the front piston position 28 is a dead center position ( Has passed through the top layer of rocker 45 with coupling 44). During the movement, the coupling joint 14 describes a pitch circle 54 and the coupling joint 55 describes a smaller pitch circle 56.

A plurality of prongs 58 are fastened on the scraper plate 16. Each tine 58 (Fig. 4) consists of an isosceles angle steel, the two legs 59 over a third of the length, starting from the lower edge to the short end to just below the apex 60 and from the lower edge to the long end to the apex 60 are cut off so that a tip 61 is formed. The tines 58 are welded to the truncated leg third on the scraper plate 16, their tips 61 forming an angle 62 of approximately 40 ° with the scraper plate 16 (FIG. 2) and when the scraper plate 16 rotates in the direction of the arrow 63 (FIG. 3) are directed forward in the same direction of rotation and move on different pitch circles around the vertical central axis 11. In the scraper plate layer 52 (FIG. 4), a first tine group 64 protrudes into the press channel 19, while the conveying direction of a middle tine group 65 extends approximately perpendicular to the longitudinal direction of the press channel. The outer tines of the tine groups 64, 65 move in the vicinity of the cylinder jacket 12 and serve to clear the cylinder space segments 66. Along the straight triangle side 51, two further tines 67, 68 are arranged one behind the other offset. Both scraper tines 67, 68 are laterally adjacent to the filling opening 18 when the scraper plate 50 is in position, of which the scraper tine 68 runs close to the knife 32.

The device works as follows:

In the shaft 1 there is a straw bale 2. The rod 4 with the knife blade 7 is connected to the piston movement by means of a cable (not shown), so that the knife blade 7 inevitably oscillates back and forth in the opposite direction to the piston 23 when the piston moves parallel to the shaft wall 3. The bale strapping 9 is opened and the bale relaxes.

When the piston 23 reaches its front position 28 (FIG. 3), the scraper plate 16 assumes the position 50. When the piston 23 moves in the direction of the arrow 70, the scraper plate 16 initially moves slowly in the direction of the arrow 63. The tips 61 of the tines 58 pierce the underside of the bale, tear off the straw and take a certain amount of straw with it. Before reaching the rear piston position 29, the scraper plate 16 performs a rapid movement and presses the amount of straw through the one filling opening 18 into the press channel 19. When the piston 23 has reached its rear position 29 (FIG. 4), the movement is reversed and the piston 23 moves in the direction of arrow 71, the scraper plate 16 first being swiveled back quickly in the direction of arrow 72. The piston 23 compresses the straw in the baling channel 19 while the tines 58 sweep along the underside of the bale without entrainment. When the piston cutting edge 31 passes the knife 32 fixed to the frame (FIG. 3), straw located outside the pressing channel 19 is separated from the straw in the pressing channel. The scraper plate 16 reaches the position 50 and the tines 67, 68 grasp the separated straw. When the piston cutting edge 31 runs into the feed pipe 36, the straw located in the upper press channel area is separated off at the transition piece 38. When the piston 23 has reached its front position 28, the movement is reversed again and the piston moves back in the direction of the arrow 70. A press pack 69 is located in the feed tube 36. During the return movement 70 of the piston 23, the scraper plate 16 moves in the direction of the arrow 63, the tines 67, 68 take the straw separated on the knife 32 with them and convey it with the straw detached from the underside of the further tines 64, 65 into the baling channel 19. The straw separated in the upper baling channel area at the transition piece 38 has meanwhile reached the bottom of the baling channel fallen and is carried and compressed by the piston 23 in the next compression cycle. When about half the height of the straw bale 2 has been processed, a light barrier (not shown) switches the scraper floor on and the next straw bale is conveyed into the shaft 1.

The density of the press packs 69 can be influenced by the length of the feed tube 36. The throughput through the charging device is controlled as a function of the heat requirement of the incinerator by the number of piston strokes per unit of time.

Claims (11)

1. Feed device for straw-burning apparatus with a bale storage arrangement (1) and a bale loosening device (16), which passes the loosened straw through a charging opening (18) to a horizontal pressing channel (19) normal to its longitudinal direction, in which a piston (23) is movable back and forth, which compacts the loosened straw and conveys it to the combustion furnace, the movements of the bale loosening device (16) and the piston (23) being co-ordinated with each other in terms of time, characterised in that a vertical shaft (1) is arranged laterally adjacent to the pressing channel (19) to receive the straw bale and beneath the shaft (1) there is provided a scraping plate (16), which is rotatable back and forth about a vertical axis (11), with tearing teeth (58) which are effective only in one direction of rotation (63), for engagement on the straw bale (2) lying above, which plate on the return movement of the piston (23) from its forward position (28) into the rearward position (29) scratches off the straw from the underside of the bale and pushes it through the charging opening (18) into the pressing channel (19).

2. Feed device according to Claim 1, characterised in that the tearing teeth (58) of the scraping plate (16) are constructed as pointed tearing prongs (59-61), which engage at an acute angle (62) into the bale surface which is to be detached.

3. Feed device according to Claim 1 or 2, characterised in that the drive of the scraping plate (16) is mechanically coupled with the piston drive.

4. Feed device according to Claim 3, characterised in that on movement of the piston from the rearward position (29) forward, the scraping plate (16) firstly moves quickly back out of the pressing channel (19), whilst in the region of the forward position (28) it performs a slow movement, and that an overload safety device is arranged in the drive of the scraping plate (16).

5. Feed device according to one of Claims 1 to 4, characterised in that at the rearward piston position (29), the scraping plate (16) assumes a position (52), in which a group of tearing prongs (64) projects into the pressing channel (19) and the conveying direction of a further group of tearing prongs (65) runs approximately normal to the longitudinal direction of the pressing channel.

6. Feed device according to one of Claims 1 to 4, characterised in that during the movement of the piston (23) into its forward position (28), the scraping plate (16) assumes a position (50), in which at least one tearing prong (67, 68) is situated laterally adjacent to a. blade (32), which is attached to the cover wall (17) at the forward end of the charging opening (18) and which co-operates with the piston (23), and that this tearing prong on its return movement takes up straw hanging for instance on the blade (32) and conveys it again to the charging opening (18).

7. Feed device according to one of Claims 1 to 6, characterised in that the scraping plate (16) is arranged to swing in a vertical cylindrical chamber (10) about an axis coaxial with the central axis (11) of the cylindrical chamber.

8. Feed device according to Claim 7, characterised in that the lower region of the shaft (1) opens into the cylindrical chamber (10) and that the shaft (1) guides a bale (2) slidably downwards in the vertical direction, whilst the bale (2) is not rotatable about the vertical axis.

9. Feed device according to Claim 7 or 8, characterised in that the cylindrical chamber (10) laterally adjoins the pressing channel (19) and opens into the charging opening (18) of the pressing channel (19).

10. Feed device according to one of Claims 1 to 9, characterised in that the pressing channel cross-section is upwardly enlarged in the region of the charging opening (18) and where it joins on to the charging opening (18) is reduced to the cross-section of the feed tube through a transition piece (38) which is constructed as a counter cutting edge and co-operates with the piston (23).

11. Feed device according to one of Claims 1 to 10, characterised in that in the lower region and within the shaft (1) a blade (7) is arranged, which is movable back and forth automatically in the opposite direction to the piston (23), to cut up the bale binding (9) of the straw bale (2).

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